This bacterium is responsible for several serious infectious diseases today, including syphilis, yaws, and bejel. The findings, published in the esteemed journal Science, push back the documented genetic presence of treponemal infections in the Americas by more than 3,000 years, offering unprecedented insights into their deep evolutionary past. The discovery challenges long-held assumptions about the origins and global spread of these debilitating diseases and underscores the immense potential of paleogenomics to unravel complex narratives of human health and pathogen evolution. A Glimpse into the Ancient Past: The Tequendama 1 Site The ancient human remains, from which the Treponema pallidum genome was recovered, were meticulously excavated from a rock shelter known as Tequendama 1, located near present-day Bogotá. This site is renowned among archaeologists for its well-preserved evidence of early human occupation in the high-altitude Sabana de Bogotá, dating back over 10,000 years. The specific individual from whom the pathogen’s DNA was isolated lived approximately 5,500 years ago, during a period of significant cultural and environmental change in the region. The meticulous archaeological work at Tequendama 1, spearheaded by researchers like Miguel Delgado of the Universidad Nacional de La Plata in Argentina, provided crucial context for the human skeleton itself, laying the groundwork for subsequent genetic investigations. The remarkable preservation of DNA in these ancient remains allowed researchers to embark on a paleogenomic journey. By analyzing the genetic material, they were able to identify and reconstruct the complete genome of Treponema pallidum, extending the known genetic history of this pathogen by a staggering 3,000 years beyond previous records. This formidable evidence lends considerable weight to the hypothesis that treponemal diseases were circulating in the Americas far earlier than previously documented, contributing a critical piece to the puzzle of their global distribution and evolution. The Power of Paleogenomics: Unveiling Hidden Histories "Our findings show the unique potential of paleogenomics to contribute to our understanding of the evolution of species, and potential health risks for past and present communities," stated geneticist Lars Fehren-Schmitz at the University of California, Santa Cruz, highlighting the transformative capacity of this relatively new scientific discipline. Paleogenomics, the study of ancient DNA, allows scientists to directly analyze the genetic material of long-dead organisms, including pathogens, offering a molecular window into past epidemics, evolutionary divergences, and host-pathogen interactions. The challenges in paleogenomics are substantial, primarily due to DNA degradation over millennia. Ancient DNA fragments are typically short, damaged, and often heavily contaminated with microbial DNA from the burial environment. Despite these obstacles, advances in high-throughput sequencing technologies and bioinformatics have made it increasingly possible to recover and reconstruct ancient genomes. In this particular study, the sheer depth of sequencing performed on the human remains—generating approximately 1.5 billion fragments of genetic data—proved to be a critical factor, enabling the reconstruction of the pathogen’s genome without the need for specialized enrichment techniques typically employed for rare DNA targets. Understanding Treponemal Diseases: A Family of Pathogens Treponema pallidum is a fascinating and medically significant spiral-shaped bacterium, or spirochete, that manifests today in several closely related subspecies, each responsible for a distinct treponemal disease. The primary subspecies are: Treponema pallidum subsp. pallidum: The causative agent of syphilis, a sexually transmitted infection known for its multi-stage progression and potential for severe systemic complications, including neurological and cardiovascular damage, if left untreated. Syphilis has had a profound impact on human history and continues to be a global health concern. Treponema pallidum subsp. pertenue: Responsible for yaws, a chronic, disfiguring, non-venereal disease that primarily affects the skin, bones, and joints. Yaws is typically transmitted through direct skin-to-skin contact, predominantly in warm, humid tropical and subtropical regions. The World Health Organization (WHO) has targeted yaws for eradication. Treponema pallidum subsp. endemicum: Causes bejel (also known as endemic syphilis), another non-venereal treponemal disease. Bejel is common in arid, impoverished regions and is transmitted through direct non-sexual contact, often within families, affecting mucous membranes and bones. A fourth treponemal disease, pinta, is caused by Treponema carateum or, alternatively, Treponema pallidum subsp. carateum. Pinta is characterized by skin lesions that change color over time but does not typically affect internal organs. It is primarily found in Central and South America. Intriguingly, no complete genome of the pathogen responsible for pinta has yet been recovered, leaving significant gaps in our understanding of its evolutionary relationships and precise classification within the Treponema genus. Despite their nearly identical genetic makeup—with differences often less than 0.2% across their small genomes (approximately 1.14 megabases)—scientists still grapple with the exact timeline and mechanisms by which these different disease forms emerged and diverged. While skeletal remains can sometimes display tell-tale signs of treponemal infections, such as characteristic bone lesions, the genetic evidence often tells a far more nuanced and complex story, bridging the large gaps between what paleopathology can infer and what ancient DNA can definitively confirm about disease evolution. A Lost Lineage: An Ancient Form of the Pathogen In this groundbreaking study, researchers confirmed that the ancient DNA belonged unequivocally to the species Treponema pallidum. However, a critical finding emerged: this ancient genome did not precisely match any of the known modern forms that cause disease today. While closely related to contemporary strains, the ancient genome represented a distinct lineage that split off very early in the bacterium’s evolutionary history. "One possibility is that we uncovered an ancient form of the pathogen that causes pinta, which we know little about, but is known to be endemic in Central to South America and causes symptoms localized to the skin," suggested Anna-Sapfo Malaspinas at the University of Lausanne and a group leader at the SIB Swiss Institute of Bioinformatics. She added, "At this time, we cannot prove this is the case, but it is a lead worth investigating further." This hypothesis offers an exciting avenue for future research, potentially illuminating the genetic origins of pinta and its relationship to other treponemal diseases. Based on sophisticated genetic analysis, scientists estimate that this ancient Colombian strain separated from other T. pallidum lineages approximately 13,700 years ago. In stark contrast, the three modern subspecies (pallidum, pertenue, and endemicum) appear to have diverged much later, approximately 6,000 years ago. These chronological markers provide compelling support for earlier research suggesting a deep and diverse history of treponemal pathogens, with significant diversification occurring in the distant past. "Current genomic evidence, along with our genome presented here, does not resolve the long-standing debate about where the disease syndromes themselves originated, but it does show there’s this long evolutionary history of treponemal pathogens that was already diversifying in the Americas thousands of years earlier than previously known," emphasized Elizabeth Nelson, a molecular anthropologist and paleopathologist at SMU. This finding adds crucial context to the "Columbian hypothesis" versus "pre-Columbian hypothesis" debate regarding the origin of syphilis, suggesting a more complex and ancient presence of related pathogens in the Americas. A Genetic Puzzle with Modern Implications Tracing the precise origins and evolutionary paths of treponemal diseases presents an enduring scientific challenge, primarily because the bacteria are remarkably similar at the genetic level. Yet, they exhibit distinct modes of transmission and can cause vastly different clinical symptoms, making their evolutionary trajectories difficult to untangle using traditional methods alone. The ability to recover ancient genomes like the one from Tequendama 1 provides an invaluable tool for resolving these complexities. "Our results push back the association of T. pallidum with humans by thousands of years, possibly more than 10,000 years ago in the Late Pleistocene," stated researcher Davide Bozzi at the University of Lausanne and SIB Swiss Institute of Bioinformatics. This profound temporal shift in our understanding suggests that Treponema pallidum may have been co-evolving with human populations since the earliest migrations into the Americas, potentially even before the end of the last Ice Age. Such a long co-evolutionary history implies a deep biological relationship that warrants further investigation. An Unexpected Find in Massive DNA Data The discovery of the ancient Treponema pallidum genome was, in fact, serendipitous. The pathogen was not the initial target of the research. The scientists were originally sequencing the individual’s DNA to investigate ancient human population history in the region. This endeavor generated an exceptionally large dataset, comprising approximately 1.5 billion fragments of genetic data – far exceeding the typical yield from ancient human samples. During routine bioinformatics screening of this massive dataset, independent teams at the University of California, Santa Cruz, and the University of Lausanne simultaneously and independently detected faint but unmistakable traces of Treponema pallidum DNA. Recognizing the immense potential of this unexpected finding, the teams decided to pool their expertise and resources to investigate the pathogen further. Despite the fact that bacterial DNA constituted only a tiny fraction of the total genetic material recovered, the extraordinary depth of sequencing allowed the team to reconstruct the pathogen’s nearly complete genome without resorting to specialized enrichment techniques that selectively target microbial DNA. This highlights a significant methodological breakthrough: high-depth shotgun sequencing of host DNA can sometimes yield sufficient pathogen DNA, even from seemingly unaffected tissues. Conventionally, most ancient genomes of Treponema pallidum have been recovered from teeth or bones that exhibited clear pathological signs of disease, such as periosteal reactions or gummatous lesions. In a notable departure from this trend, the Tequendama 1 skeleton showed no visible evidence of treponemal infection. Furthermore, researchers sampled a tibia, or shin bone, which is not as commonly used for ancient DNA studies as petrous bones (from the skull) or teeth, due to its lower DNA yield and higher porosity. The success of this approach suggests that even bones without obvious disease markers can preserve invaluable genetic information, expanding the pool of potential samples for future paleogenomic studies. Why Ancient Disease History Matters Today The study of ancient diseases, or paleopathogenomics, is far from a purely academic exercise. By meticulously learning how infectious diseases emerged, diversified, and adapted in the past, scientists gain crucial insights that can help them better anticipate how pathogens might evolve in the future. This knowledge is directly applicable to modern public health strategies, informing our understanding of disease dynamics, antibiotic resistance, and vaccine development. Understanding the long-term evolutionary trajectories of pathogens like T. pallidum can offer clues about their adaptability and potential resurgence. Before formally publishing their groundbreaking results, the research team demonstrated a strong commitment to ethical research practices. They actively shared their findings with communities in Colombia, recognizing the profound historical, medical, and cultural significance of the discovery for the country. This involved consulting with local scholars, students, and community members, as well as engaging with key stakeholders through presentations and interviews. All necessary permits for the export and study of the ancient remains were scrupulously obtained, ensuring adherence to national and international regulations. "This process was essential because the findings are deeply connected to Colombia’s medical and cultural history," affirmed Miguel Delgado. "Engaging scholars, students, and Indigenous and non-Indigenous community members ensures the results are ethically communicated and interpreted in partnership with local communities. This approach builds trust, supports responsible stewardship of sensitive discoveries, and reinforces local ownership of knowledge." This model of community engagement sets a high standard for paleogenomic research, particularly when dealing with human remains and their associated cultural heritage. An International Collaborative Endeavor The success of this complex research undertaking is a testament to the power of international collaboration, bringing together a diverse array of expertise from multiple institutions and countries. In addition to Elizabeth Nelson, Davide Bozzi, Anna-Sapfo Malaspinas, Miguel Delgado, and Lars Fehren-Schmitz, the research was notably co-led by Nasreen Broomandkhoshbacht, now at the University of Vermont. The broader international team included Kalina Kassadjikova of the University of California, Santa Cruz; Jane Buikstra of Arizona State University, a leading figure in paleopathology; Carlos Eduardo G. Amorim of California State University, Northridge; Melissa Estrada Pratt of the Instituto Colombiano de Antropología e Historia in Bogotá, Colombia, ensuring local expertise; Gilbert Greub of the University of Lausanne and Lausanne University Hospital in Switzerland; Nicolas Rascovan of the Institut Pasteur in Paris, renowned for his work on ancient pathogens; and David Šmajs of Masaryk University in the Czech Republic, an expert on Treponema pallidum genetics. This multidisciplinary and international effort underscores the collaborative spirit essential for addressing grand challenges in ancient disease research. Looking Ahead: Future Research and Implications This discovery opens numerous avenues for future research. Scientists will likely intensify efforts to recover more ancient Treponema pallidum genomes, particularly from other regions of the Americas and from different time periods, to further refine the evolutionary tree of the pathogen. The specific characteristics of this lost lineage could provide crucial insights into the genetic determinants of virulence, host specificity, and disease manifestation, potentially shedding light on why certain subspecies cause different clinical syndromes today. Furthermore, the successful recovery of a pathogen genome from a tibia without visible disease markers broadens the scope of potential samples for paleogenomic studies. It encourages researchers to re-examine previously excavated human remains that might not have been considered suitable for pathogen screening, potentially uncovering a wealth of new information about ancient diseases. This study not only rewrites a significant chapter in the history of treponemal diseases but also exemplifies the ongoing revolution in paleogenomics, continually pushing the boundaries of what we can learn from the ancient past. Post navigation New nasal vaccine shows strong protection against H5N1 bird flu
